Accurate Hartree-Fock energy of extended systems using large Gaussian basis sets

TL;DR

This paper introduces two advanced methods to accurately compute Hartree-Fock energies for solid LiH using large Gaussian basis sets and periodic boundary conditions, achieving high precision in thermochemical properties.

Contribution

It presents two novel strategies for precise Hartree-Fock energy calculations of extended systems with large basis sets and periodic conditions, including a supercell approach and an extrapolation method.

Findings

Hartree-Fock energies for LiH were obtained with sub-meV accuracy.

The two methods showed significant agreement in results.

Accurate Hartree-Fock cohesive energy, lattice constant, and bulk modulus were reported.

Abstract

Calculating highly accurate thermochemical properties of condensed matter via wave function-based approaches (such as e.g. Hartree-Fock or hybrid functionals) has recently attracted much interest. We here present two strategies providing accurate Hartree-Fock energies for solid LiH in a large Gaussian basis set and applying periodic boundary conditions. The total energies were obtained using two different approaches, namely a supercell evaluation of Hartree-Fock exchange using a truncated Coulomb operator and an extrapolation toward the full-range Hartree-Fock limit of a Pad\'e fit to a series of short-range screened Hartree-Fock calculations. These two techniques agreed to significant precision. We also present the Hartree-Fock cohesive energy of LiH (converged to within sub-meV) at the experimental equilibrium volume as well as the Hartree-Fock equilibrium lattice constant and bulk modulus.